Idiopathic Acute Transverse Myelitis: Outcome and Conversion to Multiple Sclerosis in a Large Series

Calvo et al. published an article in 2013, describing patients who were initially diagnosed with idiopathic acute transverse myelitis (IATM) who then converted to multiple sclerosis.  They reviewed the medical records from 87 patients who were diagnosed with IATM and who had never presented with neurological symptoms prior to their first attack of transverse myelitis.  The authors excluded two patients who were positive for the NMO antibody, bringing the total number of patients they studied down to 85.  They then split these 85 patients into a group that remained with a diagnosis of IATM and a group that converted to MS.  Eleven (13%) of the patients converted to MS, and 74 (87%) kept the diagnosis of IATM. Those patients who converted to MS converted at a median of 1.2 years after the first neurological event.

Lesions were found via MRI in the cervical spine (36.5%), thoracic spine (38.8%), and lumbar spine (12.9%), and there was no statistically significant difference between the groups in terms of where lesions were located in the spine.  The patients also had their cerebrospinal fluid tested for oligoclonal bands, which are bands of proteins that are used by the immune system to attack things like viruses and bacteria. Calvo et al. found that those with oligoclonal bands were more likely to convert to MS than those who did not have them.  Five out of the 15 patients with oligoclonal bands converted to MS, while one out of 44 patients without oligoclonal bands converted to MS.  They also found that those who were younger at the onset of symptoms were more likely to convert to MS than those who were older.  Calvo et al. also analyzed patients’ CSF for pleocytosis, which is an increased white blood cell count. They found pleocytosis in only 23.4% of the patients; this finding is in contrast to other studies, where 42%-62% of patients had pleocytosis.

Twenty-six patients (30.6%) had longitudinally extensive transverse myelitis (LETM), which is a descriptive term for myelitis that extends more than three vertebral sections.  Those with LETM had greater long-term disability scores than those with short myelitis.  Two of the patients with LETM converted to MS, and converted one month and seven months after the initial attack.  Urinary sphincter dysfunction was also associated with a higher disability score.  Calvo et al. conclude that at least 13% of patients who meet the diagnostic criteria for IATM will convert to MS.

This summary was written by Gabrielle (GG) deFiebre, Research Associate at a Public Health non-profit in New York City who was diagnosed with Transverse Myelitis in 2009. GG volunteers with The Transverse Myelitis Association. 

Original research: Calvin AC et al. Idiopathic acute transverse myelitis: outcome and conversion to multiple sclerosis in a large series. BMC Neurol. 2013;13(135):1-8.